Nickel-modified Poly(aniline-Co-pyrrole) As Electrocatalyst for Electrochemical Oxidation of Methanol in Direct Methanol Fuel Cell Application

The construction and assessment of an effective, cost-efficient anode catalyst for methanol oxidation reactions (MOR) are crucial in direct methanol fuel cells (DFMC) applications. This work unveils a quick, simple, yet effective method for synthesizing poly(aniline-co-pyrrole) using the “chemical oxidative polymerization” technique and creates an affordable and stable anode catalyst for DMFC applications. The chemical oxidative polymerization approach was employed to copolymerize aniline and pyrrole with incorporation of nickel, and the electrocatalyst showcased remarkable activity towards methanol oxidation reaction (MOR). Physiochemical characterizations such as scanning electron microscopy, FT-infrared spectroscopy, Raman spectroscopy, and thermogravimetric analysis were performed to validate the incorporation of transition metal nickel into the copolymerized conducting polymers (aniline-co-pyrrole), abbreviated as PANiPPy. Electrochemical techniques like cyclic voltammetry, chronoamperometry, and electrochemical impedance spectroscopy (EIS) were used to investigate the capability of the electrocatalysts to oxidize methanol in alkaline conditions. The electrode material NiPANiPPy displayed a higher oxidation current density 280.60 mA/cm2 from the cyclic voltammogram of the electrocatalysts in 1 M KOH + 1 M methanol compared to the other synthesised electrocatalysts since nickel provides a low onset potential while the copolymers PANiPPy provide good conductivity and mechanical stability. Moreover, NiPANiPPy exhibits the lowest current rate loss and a substantially higher current density among them after 3600 s with the highest current density of 100 mAcm−2. NiPANiPPy was also observed to have the lowest solution resistance with 0.8 Ω compared to other electrocatalysts in EIS spectra. Thus, the synthesized electrocatalysts has potential applications as an enhanced anode electrode for DMFC.